This invention relates to pumping apparatus particularly adapted to be portable and especially suited for pumping materials of high viscosity, although it should be understood that the technology described herein lends itself to stationary pump apparatus as well. Pumping devices have been known for a long period of time and, indeed, there have been many developments allowing the pumping devices to be portable. However, typical portable pumping systems are not capable of pumping highly viscous materials such as caulking compounds, sealants, tars, and the like. The reason that these materials present difficulties viscous materials tend to cavitate, that is, to form a cavity as a portion is pulled off of the main body of material. Presence of such open spaces makes a traditional pump inoperative since they depend upon a continuous supply of material to maintain the pumping operation.
In order to pump high viscosity materials, the prior art has relied upon utilization of air rams wherein the pump inlet includes a follower plate that is driven through the material to be pumped by compressed air cylinders in order to prevent cavitation. An example of such a system is a pump sold by Johnstone Pump Company of Troy, Mich. These systems accomplish the object of pumping highly viscous materials, but they have a disadvantage in that they are noisy and require a large capacity, high pressure compressed air source for operation. Such compressed air systems, which can supply a large volume of compressed air at several hundred pounds of pressure, are large, bulky and difficult to transport. Accordingly, the air ram pumps are somewhat suitable in large scale operations, such as factories, where a compressed air system may be centrally located and the air ram pump that it affects location.
In applications where it is desirable to have a portable pump, the air ram pump systems are difficult to utilize since not only must the pump system be moved from location to location, but also a compressed air system must be transported along with the pump. Accordingly, there remains a need for a portable pump device which is adapted to pump highly viscous materials without requiring a source of highly pressured, compressed air. There is a need for such system to be easy to use and economical in production. The present invention accomplishes these needs by its arrangemet of a progressive cavity pump with follower plate and an electric driving motor and drive shaft onto a portable, vertical slide rack which eliminates the need for a compressed air source and still provides the necessary driving force for the follower plate through the viscous material.